In the packaging field, it is known to use a web of heat-shrinkable material to wrap monobloc articles, predominantly of prismatic shape, or more frequently groups of individual articles formed, for example, by containers for products, more particularly food products and the like, having a monolithic prismatic shape referred to hereafter for simplicity as articles, by means of automatic machines which operate discontinuously or continuously and constructed such that they may wrap the heat-shrinkable material about the individual articles to be wrapped in a variety of ways.
It is conventional in this packaging technique to wrap the article to be wrapped with the web of heat-shrinkable material in the direction of the movement of the article such that the material projects beyond two transversely opposite faces of the article and then to pass this wrapped article through a tunnel furnace to cause the material to adhere by heat-shrinkage to the wrapped faces and to the two transversely opposite faces of the article by folding the corresponding material over these latter two faces.
The apparatus of the invention may be advantageously used in automatic machines for the above-mentioned use which operate discontinuously or continuously and particularly in the type of continuously operating machine disclosed in the Italian Patent Application No. 3349 A/83 (see U.S. Pat. No. 4,574,565 issued Mar. 11, 1986).
A machine of this type for wrapping articles supplied in a uniformly spaced manner by means of a continuously moving conveyor with sheets cut in succession from a strip of heat-shrinkable material of a width such as to project beyond two transversely opposite side faces of the article and brought in succession by suction take-up means along their respective longitudinal edges across the feed path between successive articles so as to be folded over the front, top and rear surfaces of a corresponding article in the shape of an upturned U with the end portions of this U extending beyond the respective lower face is substantially provided with the conveyor formed by two adjacent conveyor belt sections and with the take-up means supported between the two adjacent belt sections. The adjacent zones of the two belts are wound on at least a corresponding pair of return rollers supported by a carriage which may be moved in an alternating manner parallel to the conveyor direction and the take-up means are disposed such that they may be moved in an alternating manner vertically and parallel with respect to the movement of the carriage.